For most of his life, Katsuki didn't care about having a relationship. He was laser-focused on his work as a hero, and a family would only distract him. When the others start to marry and even have kids, he is rather irritated by that. But he figured the reason he had no interest in this was that he was asexual, even though this never felt completely right. Only after Izuku came out as gay, he started to question himself again. He hadn't even thought about this possibility! After an incident on Inko's 55th birthday, Katsuki is stuck thinking about his best friend all the time. Could it be? Was he in love with Izuku? No way, right?